Tuesday, October 10, 2006

Defects somewhere on the medial system?

In a previous post, I put the idea forward that thinking in terms of a defect somewhere on a circuit is a more natural way of thinking about stuttering. It naturally includes the possibility that different malfunctions are causing stuttering and that they all have roughly the same basic symptoms (because they have malfunctions on the same circuit).

The best candidate of such a circuit might be the medial premotor system (the basal ganglia and SMA). Per Alm has put this forward in his PhD thesis. I have written about it extensively, for example here. Roughly, the brain has two parallel dual premotor systems: the medial for automatic speech (where we emphasise on content of speech), and the lateral (where we emphasise on the form of speech). Of course, if we assume that the malfunction can be anywhere along the medial system (and the fibers connecting it to speech/language regions), we will not be able to get clear experimental observations as for each defect another region is affected?